Re: [PATCH 04/12] perf tools: Allow BPF program attach to modules

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Fri, Nov 13, 2015 at 12:29:13PM +0000, Wang Nan escreveu:
> By extending the syntax of BPF object section names, this patch allows
> user to attach BPF programs to symbol in modules. For example:
> 
>  SEC("module=i915\n"
>      "parse_cmds=i915_parse_cmds")
>  int parse_cmds(void *ctx)
>  {
>      return 1;
>  }
> 
> Implementation is very simple: like what 'perf probe' does, for module,
> fill 'uprobe' field in 'struct perf_probe_event'. Other parts would be
> done automatically.
> 
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: David Ahern <dsahern@gmail.com>
> Cc: He Kuang <hekuang@huawei.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kaixu Xia <xiakaixu@huawei.com>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Zefan Li <lizefan@huawei.com>
> Cc: pi3orama@163.com
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Link: http://lkml.kernel.org/n/1445915248-175553-1-git-send-email-wangnan0@huawei.com
> ---
>  tools/perf/util/bpf-loader.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
> index 5f5505d..8d78785 100644
> --- a/tools/perf/util/bpf-loader.c
> +++ b/tools/perf/util/bpf-loader.c
> @@ -117,6 +117,14 @@ config__exec(const char *value, struct perf_probe_event *pev)
>  	return 0;
>  }
>  
> +static int
> +config__module(const char *value, struct perf_probe_event *pev)
> +{
> +	pev->uprobes = false;
> +	pev->target = strdup(value);
> +	return 0;
> +}

check strdup return

> +
>  static struct {
>  	const char *key;
>  	const char *usage;
> @@ -129,6 +137,12 @@ static struct {
>  		"Set uprobe target",
>  		config__exec,
>  	},
> +	{
> +		"module",
> +		"module=<module name>    ",
> +		"Set kprobe module",
> +		config__module,
> +	}

Named initializers, please.

>  };
>  
>  static int
> -- 
> 1.8.3.4